Foil laminate



June 2.1, 1955 M. vH. PINTELL 2,711,380

FOIL LAMINATE Filed Nov. 7, 1952 Fon. LAlvnNATE v Y Y Milton H. Pinion, Richmond, va., @signor to Reynolds Metals Company, Richmond, Va., acofrporation of`V Delaware o o v y o vApplication November 7, 1952, Serial No. 319,426 3 Claims. (Cl. 154-,453)

This invention relates to laminate structures madeirom a metal foil and a cellulosic sheet or web as wellas to foil V paper-wood laminates permanently secured together.

It is an object of this invention to provide a laminate sheet including and adapted to bond a layer of metal foil,

particularly aluminum foil, to plywood and other wood surfaces or faces, which will have universal use not withknown inthe art thereby concealingthe knots; barrierlaminarte Ystock toi? 'impede passage ofuid material, e.g.`in cooperage staves, wood tanks, Ywood piping, etc.;,improvedgrigidity of'sing'le standing the porosity or lack of substantial porosity of the wood, and which is adapted to be strongly bonded to. said wood by the application of heat and pressure.

A further object of the invention is to enable the use of embossed metal foil laminate as the wood covering layer in such a manner that adequate heat and pressure may be used to bond the foil to the woodwhile main? taining the embossed surface. i

A further object of the invention, pertinent to the last stated object, is the reinforcement of theembossedlami` nate by a like embossed underlying sheet which consists of a major content of adhesive and a minor content of cellulosic fibers. l

A further object of the invention-is tdreducethe cost of the laminated product by overcomingl problemsincident to the use of twoderent adhesive mediums, the invention resulting in a compatible interaction 'between the high cost adhesive directly applied to the foil and a low cost adhesive which impregnates the cellulosic ber, both adhesives being condensed and adapted to be cured under the application of heat and pressure during lthe application of the .laminate to a woodlsurface.V

These and other objects will become apparent."upon'v reading the following disclosure.

This application is a contnu'ation'in part of SerialV No.k 109,410 filed August 9, 1949,`r now abandoned.

The drawing is aV perspective viewfshowing an embodii ment of the invention, broken away in part.

According to this invention a metal foil, which maybe i' smooth or embossed, for example, aluminum Afoil,'.is,se cured to a cellulosic web orlayer, for example, paper'or a cotton web by means of an elastomeric adhesive coml' i Y y 1Cor@ datedherein. I Y Y The term `partially cured' resin as used'hereinineans a resin that is solvent soluble,"forexamplelin methyl ethyl l ketone and in other solvents fused for dissolvingsaid resin priorY toapplicatiorn. Thefterm. advanced kiB, lsta'tefjor `vphenolic condensationtasusedyherein, means-suche def gree of condensation that .at leastl`60% of-thecondensation or curing reactionthaslbeen completed lheTterm'j initial `B stage"ofcondensationwas used hereinmeans, ai` vi phenolic resin having such a degree of condensationporf" Vvoffthe'condensation reaction' has cure, that up to 40 been'completed.V The usesk of; this i wood by giving :itja permanently ysecured metal'facing wood lplyfoil laminates;prevention of. grainraising'V by I ture into a layer of grained/wood, ete..` t Y The adhesive of the laminate'will-withstand.high h'u-f midity and evencontact with waterY for prolonged periods. o of-time. kThus the foil laminate of this inventionis suitablefor use Yin the construction of boats, because they 'l metal resists water and the adhesive at thei juncture ozthf panels itself `is extremely `resistant to'wa'teripefnfetratiom Theadhesive. of vthis 'inventionVT is adaptedf tof set at Y the. relatively high temperatures fconimntozpthehot press Y' plywood industry.` The.use `of, such'kan adhesive'permits Y the. foil laminatesto, be. removedifom therpresses'while f stillfhot. The ,adhesive is.thermosettingicharacter andV Vthus will permit the removal of a hot laminated` panel after fthe time interval required to cure the adhesive.

i ranges from about 30% kto about 70%V 'The use of thermoplastic adhesivein the plywoodjin;v dustry has many disadvantages, `e.I gacellulose nitrateis l f susceptible to ignition, kwhile other thermoplastics areobweb` suchas woven-,textile iriaterialfk Conventional ad-k hesiyes for foil, such asthe vinyl chloracetate polymers, i' acrylic, Yor methacrylic `acid esters are Vincompatiblegwith i and noft suitable for bonding to a phenolic'riesin saturated cellulosic web or backing.

VAlls'o*according to this invention, thev phenol-formalde--k` y Y hyde resin concentrationof the saturatedY cellulosickweb of -the total weight,

'of the ,treatedwebfor paper. Whenjthel foillaminate havprising a Vacrylonitrile-butadiene'resin and a phenolic.,

resin, said cellulosic layer beingtreated, preferablytsartr-V I."

urated with phenolic resin, said elastomeric adhesive being in such a stage of condensation so as to effect a faster curing than the curing of the phenolic resinin` the cellulosic layer whereby heat curing takes place first in elastomeric adhesive, and only then, e. secor'1darily,vdoesv thecuring of the phenolic `resin in the cellulosic layer take place.

The cellulosic layer may be disposed against a layer of wood during the curing of the aluminum foil adhesively secured `to paper laminate so that curing vof the laminate effects a union of the paperlayer to its adjacentf ly disposed layer of wood. I I f l A t The phenolic resin in the elastomeric resin adhesive must be a partially cured resin in the advanced B stage ofV condensation, but` the phenolic resin of the cellulosic orY paperlayer may be inthe A stage or'initialB stage; These A and Bstages of phenolic condensation are well ing va paper or cellulosic web. saturatedywith,phenolicf' o mkflat woodjsurface'andmolded i thereto, afconsidrerable amount of the phenolic:,resin. Y

migratesfro'm-the paper into theV pores of the QwoodThe resin is/placed against a acrylomitrile butadiene thennosetting adhesives of `this inventionlprovideyfor suclija' rate'of.tlie'rn'ro'setting,thatv itis-substantially faster thanfthe s'etting?jorieuri-g` oflhe phenolic 'resin inthe paper l layer; therebyf preventing migration"of the acrylofnitrile butadieney resininto they paper orcellulosicweb duringrthe hot pressing V,of tlioerfoilpaper laminatefto a wood`i:'ou i1dation,IcorefofV hacking;

Thus, 'thisfinvrentionz provides 'forl an adhesive l `having lther'm'osetting` {properties,1-c lisposed .betweenin af-'I'metalfoil Y 1 andiasprhenolic resin saturatedcellulosic web, and further having a substantially faster-jcure than the phenolic resin disposed in l Athe cellulosic web. Further, themresin'compositions of-this invention are adapted to liberate, solvents,A Y

without any substantialrersiduevof volatiles remainin'gafiter application,- thereby preventingV blows beneaththe lvim- Y l 2,711,330' 1 Patented June .21, .71955. Y

andither'eforeL need not be' furtherf'elucio,` f i nvention are many, such burn# proofing of Ywooden furniture yand other ,combustible solids; burnproong of yotherwise burnable" laminates," such as, plywood; Yenhancing the value-of knotgirevalentv pervious foil due to volatization of volatiles during the hot pressing of the laminate.

Examples of the thermosetting adhesive compositions used between the foil and the phenolic resin are:

Example No. l: Per cent by weight Acrylonitrile-butadiene polymer (18% acry- The amine constituents of this formula are used both to stabilizethe viscosity of the initial adhesive solution and to provide resistance to atmospheric oxidation to the acrylonitrile butadiene co-polymer.

Example No. 2:

Acrylonitrile-butadiene polymer (26% acry- Example No. 3: Percent by weight Acrylonitrile-butadiene polymer (3.5% acry- Per cent by Weight i lonitrile-.65% butadiene) 25.50 Phenolformaldehyde resin 21.25 "d Monoheptyl diphenylamine .50 Diheptyl diphenylamine 1.25 Methyl ethyl ketone 51.50

Example No. 4 (illustrating high acrylonitrilebutadiene-polymer ratio to low phenol-fornial dehyde resin component):

Per cent by weight Acrylonitrile-butadiene polymer (26% acryl0nitrile-75% butadiene 26.25 Phenol-formaldehyde resin 5.50 Monophenyl diortho xenyl phosphate 1.75 Di-.beta naphthyl-para phenylenediamine 1.75 Methyl ethyl ketone 64.75

In Examples 2 and 4 monophenyl diortho xenyl phosphate is used as a plasticizer to effect better compatibility between the phenolic resin and the acrylonitrile butadiene co-polymer.

Example No. 5 (illustrating high phenol-formaldehyde resin ratio to low acrylonitrile-butadiene polymer component):

Per cent by weight Example No. 6l (illustrating theuse of low proportion fof phenolic resin and additionof therrnionic carbon black to reduce moisture absorption of;

tw.: s..

adhesive, when abnormally high water resistance is necessary):

' Per cent by weight Acrylonitrile-butadiene polymer (26% acry- 1onitrile-64% butadiene) 22.75 Phenol formaldehyde resin 20.50 Thermionic carbon black 6.25 Monophenyldiortho xenyl phosphate 3.25 Phenylbeta naphthylamine .25 lsopropoxy diphenylamine. .50 Diphenylpara phenylenediamine .25 Methyl ethyl ketone 46.25

The formula of Example 6 is particularly adapted for use in foil laminates used in the construction of boats. This formula contains therrnionic carbon black to further reduce the moisture adsorption of the thermosetting adhesive. Channel blacks are usable in lieu of thermionic blacks but-are not preferred because of their inferior characteristic relative to resistance to moisture pick-up.

In preparing the thermosetting adhesive used to unite the metal foil to the phenolic saturated cellulosic web, the acrylonitrile butadiene co-polymer is dissolved in the solvent, e.v g. methyl ethyl ketone, together with any viscosity stabilizers and plasticizers used in the formula. Next, the phenolic resin is added to the prepared solution and mechanically mixed to effect complete solution.

Dissolving of all the solid components simultaneously in the methyll ethyl ketone may effect an undesirably high temperature, sulciently elevated to deleteriously effect the curing property of the phenolic resin used in conjunction with the acrylonitrile butadiene co-polymer. However, simultaneous solution of the dissolvable components in the methyl ethyl ketone is feasible if adequate cooling is provided to prevent an undesirable rise in temperature.

Where thermionic black constitutes a part of the formula, the black solid material is first milled into the acrylonitrile butadiene co-polymer and then dissolved in the solvent.

The thermosetting adhesive is applied in the form of a solution to the metal foil, for example, aluminum foil and thereupon the solvent is allowed to completely evaporate at a temperature sufficiently low so as not to eifect the curing properties of the adhesive.

Clearly,`this invention comprises adhesively joining a metal foil to a phenolic resin treated paper sheet using a thermosetting adhesive, and thereafter bonding said foil adhered paper to a wood layer, thereby effecting a first thermoset bond between the foil and the phenolic resin treated paper and a second thermoset bond between the phenolic resin treated paper and the wood, in one hot press operation, the curing of the thermosettin'g adhesive being effected prior to that of the phenolic resin which joins the paper to the wood layer. consecutive curing of the over-all laminate in the hot press, i. e. rst the curing of the adhesive thermosetting resin disposed between the metal foil and the paper layer,

and secondly between the phenolic resin treated paper layer and wood layer.

Having described my invention, what I claim and desire to secure by Letters Patent is as follows:

1. A laminate structure comprising metal foil, a partially cured phenolic resin saturated paper layer, a thermosetting adhesive comprising acrylonitrile butadiene co-` In short there is aV nitrile butadiene resin plus phenolic resin adhesive layer permanently bonding said foil to said paper, 'and a wood adhesive acrylonitrile butadiene resin containing phenolic resin having at least 60% completion of the condensation reaction adhered to said foil, and a paper web saturated 10 with slow curing phenolic resin having up to 40% completion of the condensation reaction.

vUNITED STATES PATENTSV Saunders et al. "May 22, V1945 Heft1er` VFeb.18, McClary Apr."1,19477VV Gibbons et al. Aug. 16, 1949 FQREIGNPATENTS GreatV Britain June 4, 

3. AS AN ARTICLE OF MANUFACTURE, A FOIL LAMINATE CONSISTING OF A METAL FOIL, A LAYER OF RAPID CURING ELASTOMERIC ADHESIVE ACRYLONITRILE BUTADIENE RESIN CONTAINING PHENOLIC RESIN HAVING AT LEAST 60% COMPLETION OF THE CONDENSATION REACTION ADHERED TO SAID FOIL, AND PAPER WEB SATURATED WITH SLOW CURING PHENOLIC RESIN HAVING UP TO 40% COMPLETION OF THE CONDENSATION REACTION. 